1. Field of Invention
This invention relates to a blanket for covering it least a portion of the body of a human, or other animal, in order to bath the body portion in a conditioned gas. More specifically, the present invention is related to an inflatable thermal blanket having air flow channels for directing a conditioned gas, such as, for example, heated air, to a selected portion of the body of a user and preventing the conditioned gas from being directed at other portions of the body.
2. Description of the Related Art
Inflatable thermal blankets which are used to communicate a conditioned gas, such as heated or cooled air, to a patient are known in the art. Such thermal blankets typically have an inflatable portion provided with an inlet port for placing the inflatable portion in fluid communication with a source of pressurized, conditioned gas such that the inflatable portion can be selectively inflated. The inflatable portion generally has an inner surface which is gas pervious, or which is otherwise adapted to communicate the conditioned gas used to inflate the blanket to the user. Such thermal blankets are often used to treat conditions such as hypothermia, or used to reduce the body temperature of a user in circumstances where the body temperature is inappropriately high. For example, where a patient is being treated for hypothermia, at least a portion of the patient's body is covered with the thermal blanket, and warm air is pumped into the inflatable portion. The warm air used to inflate the inflatable portion is thereafter communicated through the inner surface of the inflatable portion so as to bath the body portion covered by the blanket in warm air. Examples of such thermal blankets are disclosed in U.S. Pat. Nos. 5,184,612; 5,304,213; and 5,324,320.
Whereas prior art thermal blankets serve to deliver conditioned air to a patient, the temperature of the air being communicated through the inner surface of the inflatable portion, and the surface temperature of the inner surface, can vary greatly over the area of the inner surface. For example, if heated air is pumped into the inflatable portion through the inlet port, the air within the blanket near the inlet port tends to be substantially higher in temperature than the air within the blanket which is remote from the inlet port. Accordingly, the inner surface of the blanket proximate the inlet port, and the air communicated to the patient through the inner surface of the blanket proximate the inlet port, can be uncomfortably, or damagingly, hot when the blanket is otherwise communicating air of the desired temperature to the patient. Whereas the temperature of the air entering the inlet port can be reduced to avoid uncomfortable, or damaging, hot spots near the inlet port, such a reduction of temperature can compromise the overall effectiveness of the thermal blanket.